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SSR02 fixed voltage, fine adjustement and DZ1 Qs

Started by Malefoda, March 27, 2010, 03:39:34 PM

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Malefoda

Hi there,

having built +5 & -5 LT1028ACN & LM431 based SSR01 & SSR02. They all show a rock solid +/-4.98V, can't see lower on my DMM.

Now with a -15V.
Same, R12 being 499 in all SSR0x, but the DZ1 wich is a yellow Led. All starts fine with an -14.83V.

• this yellow Led is always on, isn't it supposed to go off after a while?
• what R to change in order to get -15V or better -14.98?

Regards,

Matthieu

peranders

The LED should be lit. This is a sign that you have a constant voltage across R4 and the regulator is regulating.

If you are using opamps it doesn't matter if you have 14.67, 14.83 or even 15.17 V as long it's stable. Around VR1 you have empty places for addition resistors. You can also tweak the gain a bit. Also there you have extra resistor locations. If you feel that this is important for you and you are not able to calculate yourself I can help you with this. For this I want to know used resistor values and also the reference voltage, measured directly over the LM431.
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

Malefoda

Hi Per-Anders,

yes I need as close as -14,98V
Right I have all R values like in your files for download but R12 to 499R, spare parts from my first SSR01 ;)
In the building instruction it's 470R, is this one of the trick?

If changing some R values, a // mix of R to make the right one is welcome.

I have -4.84V at the first pin of the LM431.

Side question, about the -5V one, I've found the LM337 to run warm without any load, maybe because of the same -25V as the -15 SSR02? Voltage drop story?
Even if my DMM shows a stable -4.98V... I've checked LM431 and it shows 0V at that first pin but -2.49V at the second one, same 2.4 as the +5 but the first pin! Maybe no problem here it's just me getting nervous at a fly passing by ;) The SSR01 at +5 is powered by +11V and stay barely warm.

Thanks,
Matthieu

peranders

#3
Have you really used my BOM for -15V? The LM431 should have 7.50 V at the cathode. The gain should be 2 and you seems to have 3.

To see that everything is working OK. The LM431 should have 2.50 V +- 2% between ground (anode) and ref.

The regulator consumes some power so 5 V out and 25 V in will create some power losses and most of if is in the LM337. LT1028 is rather thirsty too.

Curious, but what is your need for 14.98V? (15V within 1.3‰)
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

Malefoda

Hi,
yes I've done it according to your BOM, but as I'm a bit "mindless" it's still possible that I've mixed parts or missed one
I have 4.84V between pin 2 & Grnd,
7.31 between pin 3 & Grnd,
0 at pin 1 & Grnd.
2.472V betwenn pins 2 & 3

The computer is away from the stuff so I can't keep in mind what pin is what in wich order :'(

The Reg is for a TDA1541A S1 wich perfom best with a nice -10V between its negative rails. I also like to "cut the hair in quarters" or "fuck the flies" (sorry french sayings to express someone very boring finding problems where there are none ;) ).

Thanks!
Matthieu

(defo a pretty kitty)

peranders

If you can tell me which resistor values you have I can calculate how to get near -15 V.
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

Malefoda

#6
Hi,
you mean the real ones, not the BOM ones?
100% BOM ones but R12 a 499R.
I'll get the precise values this noon.

Edit:
here what I have on the board, close ones showing the same are in // I suppose,
R1 0.996K
R2 0.996K
R3 2.195K
R4 100R
R6 47.05R
R8 944R
R10 925R
R11 925R
R12 499R
R13 1.952K
R14 4.79K
R16 3.743K
R17 3.743K

Voilà !

peranders

A fast calculation shows that something is wrong here. Have you measured on soldered resistors?

Have you checked my BOM and compared?
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

Malefoda

#8
Quote from: peranders on March 28, 2010, 03:13:57 PM
A fast calculation shows that something is wrong here. Have you measured on soldered resistors?
Yes, I know that's a bit stupid...

Quote
Have you checked my BOM and compared?
Yes, both pics (15 based but all R the same) & list

peranders

Can you tell me the values of the resistors, and of course the value which they are marked with?

I have a very good picture of the 15V, LM431 positive version which is exactly the same as the SSR02 when it comes to resistors.

http://sjostromaudio.com/hifi_pics/hifi_100pr/ssr01r0_15V_LM431.jpg
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

Malefoda

#10
It's the exact copy of this picture but R12 and values are:
R1, R2, R8, R11   1k0
R3, R13   2k2
R4   100R
R6, R9   47R
R7   0R0
R10   39k
R12   499R
R14   10k
R16   5k6
R17   56k
R18, R19   nothing
J1, J2   Tin jumper

Malefoda

I've checked again, it's really like this.
Hope I can make that adjustment, telle me if more tests are needed.

Matthieu

peranders

/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

Malefoda

Ok that means I'll have to remove the R and check them.
I'll report my findings.

peranders

If you have 1% resistors you can consider them as "exact". Just change the ones who are different.
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff